1. Technical Field of the Invention
The present invention relates to dermatological compositions for topical application, to processes for formulating such compositions and to their uses as cosmetic or pharmaceutical products. Said compositions are particularly useful for treating acne.
2. Description of Background and/or Related and/or Prior Art
Acne is a common multi-factor pathology that attacks skin rich in sebaceous glands (face, shoulder area, arms and intertriginal areas). It is the most commonly occurring form of dermatosis. The following five pathogenic factors play a determining role in the formation of acne:
1. genetic predisposition;
2. overproduction of sebum (seborrhoea);
3. androgens;
4. follicular keratinization disorders (comedo-genesis); and
5. bacterial colonization and inflammatory factors.
There are several forms of acne, the common factor of all being attack of the pilosebaceous follicles. Especially exemplary are acne conglobata, cheloid acne of the nape of the neck, medication-related acne, recurrent miliary acne, necrotic acne, neonatal acne, premenstrual acne, occupational acne, acne rosacea, senile acne, solar acne and simple acne.
Simple acne, also known as polymorphic juvenile acne, is the most common. It comprises four stages, but passage through all the stages is not obligatory:
stage 1 corresponds to comedonic acne characterized by a large number of open and/or closed comedones and of microcysts;
stage 2, or papulopustular acne, is of mild to moderate seriousness. It is characterized by the presence of open and/or closed comedones, microcysts, but also red papules and pustules. It mainly affects the face and leaves few scars;
stage 3, or papulocomedonic acne, is more serious and extends to the back, the chest and the shoulders. It is accompanied by a larger number of scars;
stage 4, or nodulocystic acne, is accompanied by many scars. It presents nodules and also painful voluminous crimson pustules.
The various forms of acne described above may be treated with active agents such as anti-seborrhoeic agents and anti-infectious agents, for example benzoyl peroxide (especially the product Eclaran® marketed by Pierre Fabre), with retinoids such as tretinoin (especially the product Retacnyl® marketed by Galderma) or isotretinoin (the product Roaccutane® marketed by Laboratoires Roche), or with naphthoic acid derivatives. Naphthoic acid derivatives such as, especially, 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid, which is commonly known as adapalene (the product Differin® marketed by Galderma), are widely described and acknowledged as active principles that are just as effective as tretinoin for the treatment of acne. Adapalene also has the advantage of causing fewer side effects, such as phenomena of irritation, dryness of the skin or intolerance, than the other active agents described above, which makes it a product of choice.
However, those skilled in the art are constantly seeking to improve the efficacy and tolerance of compositions containing this type of active agent. One of the solutions for improving the efficacy is to increase the amounts of active agents present in the composition or to increase the treatment times. Such modifications generally result in an increase in the induced irritation. This is why it is necessary to provide compositions that can further improve the tolerance of the active principles.